Halobacterium Expression System for Production of Full-Length Plasmodium falciparum Circumsporozoite Protein

Abstract

We recently developed a novel expression system employing the halophilic Archaeon Halobacterium sp. NRC-1 for scaled-up production and nanoparticle-display of antigenic proteins. Here, we have targeted the major human parasite Plasmodium falciparum circumsporozoite protein (CSP), which is of interest for formulation of a protective malaria vaccine. A codon-optimized synthetic gene coding the full-length CSP was inserted downstream of the strong promoter for gvpA, the major gas vesicle nanoparticle protein gene, in the pDRK expression vector, and as a fusion to the gvpC protein in the pSD expression vector for display on the surface of gas vesicle nanoparticles. We found that the pDRK-CSP expression plasmid programmed high-level production of full-length CSP and the pSD-CSP expression plasmid programmed production of a GvpC-CSP fusion protein, for display on gas vesicle nanoparticles. The Halobacterium sp. expression system provides a novel approach and a potentially valuable technical advancement for the production of P. falciparum CSP for malaria vaccine development.